Plaster board



Nov. 27 1923. 1,475,674

- L. E. ARMSTRONG PLASTER BOARD Filed May 24, 1922 jwem tor' Zozw's ZQQr-mq i/o 7 ,9.

Patented Nov. 27, 1923.

UNITED STATES LOUIS E. ARMSTRONG, OF FORT DODGE, IOWA.

PLASTER BOARD. r A

Application filed May 24,

To (all whom it may concern:

Be it known that I, LoUis E. Aimis'rnono, a citizen of the United States, and a resident of Fort Dodge, in the county of Vebster and State of Iowa, have invented certain new and useful Improvements in Plaster Board, of which the following is a specification.

This invention relates to plaster board or the like, and has for its object the production of an improved, completely covered plasterboard, economical to produce and etficient in use.

In the manufacture of plasterboard it is desirable to cover the entire board with paper or the like. The invention accomplishes this purpose in a cheap and eflicient manner.

In the drawings, in which is presented an illustrative embodiment of the invention,

Figure 1 is a perspective view of a sheet of plasterboard containing the invention. portions of the covering sheets being rolled back for clarity.

Figure 2 is a cross sectional view of the board on a reduced scale.

Figure 3 is a perspective view of a perforated strip. forming a part of the board of the invention.

Figure 4: is an enlarged cross sectional view of a portion of the board.

Referring to the figures; the plasterboard shown comprises a sheet of body material 1 and a pair of covering sheets 2 and 3. usually of paper, the board being made, in brief. by rolling a plastic mass of gypsum or the like between the two covering sheets, which adhere thereto.

In constructing the board, according to the invention. I fold the bottom sheet 2 over the edges of the body material, the bottom sheet being made of sutlicient width for that purpose. and lay the marginal portions of the bottom sheet upon the top surface of the body material. l place the top sheet 3 of appropriate width between the margins of the overlapped bottom sheet so that ad jacent each edge of the board are the two abutting margins of the sheets 2 and 3.

in order to prevent leakage of plaster between the abutting margins t and 5 of the sheets 2 and 3, I place the strip 6 underneath these margins as shown. The strip 5 has two lines of perforating 7, and an imperforate median portion 8 which immediately 1922. Serial No. 563,217.

underlies the joint or space between the abutting margins 4: and 5.

The perforations 7 are important in contributing to the ease of manufacture of the board and its strength and durability when made. In the manufacture, under the pressure of the rolls, or whatever pressure means to be employed, the plastic mass flows upwardly through the perforations 7 and comes into intimate contact with and adheres to the under surface of the sheets 2 and 3, which are thereby sealed directly to the body material by buttons or pillars of plaster such as shown at 9, Figure 1. Fur thermore, the perforations 7 prevent the strip 6 being depressed by superposed plastic material in the manufacturing process, because that material can flow freely through those perforations without shifting the strip. The strip therefore maintains its position immediately under the sheets 1 and 2 and properly seals the joint therebetween, and serves in effectto so cover the joint that the cifect is as though the top sheet was continuous at that point.

I claim:

1. In a plasterboard or the like a sheet of body material, a sheet of fibrous covering material therefor, folded about one edge of the body material and having its margin adjacent each edge, a second covering sheet overlying the face of the body material and having its margin abutting the margin of the first sheet, a perforated strip of fibrous material underlying the adjacent imirgins to seal the joint therebetween.

2. In plasterboard or the like a sheet of body material. a sheet of fibrous covering material therefor. folded about one edge of the body material and having its margin adjacent said edge, a secondcovering sheetoverlying: a face of the body material and having its margin abutting the margin of the first sheet. a perforated strip of fibrous material underlying the adjacent margins to seal the joint thcrcbetween, said strip having perforations on either side of the joint between said margins.

In plasterboard or the like a sheet of body material, a bottom covering sheet for said body material folded over the edge thereof and terminating in a margin parallel with and adjacent to the said edge, a top sheet covering material for the body material having a margin adjacent to margin of til the bottom sheet, a strip of fibrous material underlying the joint between said margins and impressed into the body material, said strip being perforated on either side of said joint, but imperforate at the oint.

&. A joint for plasterboard covering inaterial comprising in combination a pair of covering sheets, having their margins abutv ting each other, a strip underlying both said margins, said strip being pertorated, 10

\i'hereby the plastic material may flow up- Wardiy through the perforations and adhere to the under surface of the covering sheet during the formation of the joint.

In Witness whereof, I hereunto subscribe' my name this 20th day of May, A. D. 1922.

LOUIS E. ARMSTRONG. 

